[
https://issues.apache.org/jira/browse/SPARK-31962?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Christopher Highman updated SPARK-31962:
----------------------------------------
Description:
When using structured streaming with a FileDataSource, I've encountered a
number of occasions where I want to be able to stream from a folder containing
any number of historical files in CSV format. When I start reading from a
folder, however, I might only care about files that were created after a
certain time.
{code:java}
spark.readStream
.option("header", "true")
.option("delimiter", "\t")
.format("csv")
.load("/mnt/Deltas")
{code}
In
[https://github.com/apache/spark/blob/f3771c6b47d0b3aef10b86586289a1f675c7cfe2/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/InMemoryFileIndex.scala],
there is a method, _listLeafFiles,_ which builds _FileStatus_ objects
containing an implicit _modificationDate_ property. We may already iterate the
resulting files if a filter is applied to the path. In this case, its trivial
to do a primitive comparison against modificationDate and a date specified from
an option. Without the filter specified, we would be expending less effort
than if the filter were applied by itself since we are comparing primitives.
Having the ability to provide an option where specifying a timestamp when
loading files from a path would minimize complexity for consumers who leverage
the ability to load files or do structured streaming from a folder path but do
not have an interest in reading what could be thousands of files that are not
relevant.
One example to could be "_filesModifiedAfterDate_" accepting a UTC datetime
like below.
{code:java}
spark.readStream
.option("header", "true")
.option("delimiter", "\t")
.option("filesModifiedAfterDate", "2020-05-01T12:00:00")
.format("csv")
.load("/mnt/Deltas")
{code}
If this option is specified, the expected behavior would be that files within
the _"/mnt/Deltas/"_ path must have been created at or later than the specified
time in order to be consumed for purposes of reading files from a folder path
or via structured streaming.
I have unit tests passing under _CSVSuite_ and _FileIndexSuite_ in the
_spark.sql.execution.datasources_ package.
was:
When using structured streaming with a FileDataSource, I've encountered a
number of occasions where I want to be able to stream from a folder containing
any number of historical files in CSV format. When I start reading from a
folder, however, I might only care about files that were created after a
certain time.
{code:java}
spark.readStream
.option("header", "true")
.option("delimiter", "\t")
.format("csv")
.load("/mnt/Deltas")
{code}
In
[https://github.com/apache/spark/blob/f3771c6b47d0b3aef10b86586289a1f675c7cfe2/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/InMemoryFileIndex.scala],
there is a method, _listLeafFiles,_ which builds FileStatus objects containing
an implicit _modificationDate_ property. We may already iterate the resulting
files if a filter is applied to the path. In this case, its trivial to do an
primitive comparison against modificationDate. Without the filter specified,
we would be expending less effort than if the filter were applied by itself.
Having the ability to provide an option specifying a timestamp by which to
begin globbing files would result in quite a bit of less complexity needed on a
consumer who leverages the ability to stream from a folder path but does not
have an interest in reading what could be thousands of files that are not
relevant.
One example to could be "filesModifiedAfterDate" accepting a UTC datetime like
below.
{code:java}
spark.readStream
.option("header", "true")
.option("delimiter", "\t")
.option("filesModifiedAfterDate", "2020-05-01 00:00:00")
.format("csv")
.load("/mnt/Deltas")
{code}
If this option is specified, the expected behavior would be that files within
the _"/mnt/Deltas/"_ path must have been created at or later than the specified
time in order to be consumed for purposes of reading files in general or for
purposes of structured streaming.
I have unit tests passing under _CSVSuite_ and _FileIndexSuite_ in the
_spark.sql.execution.datasources_ package.
> Provide option to load files after a specified date when reading from a
> folder path
> -----------------------------------------------------------------------------------
>
> Key: SPARK-31962
> URL: https://issues.apache.org/jira/browse/SPARK-31962
> Project: Spark
> Issue Type: Improvement
> Components: SQL, Structured Streaming
> Affects Versions: 3.1.0
> Reporter: Christopher Highman
> Priority: Minor
>
> When using structured streaming with a FileDataSource, I've encountered a
> number of occasions where I want to be able to stream from a folder
> containing any number of historical files in CSV format. When I start
> reading from a folder, however, I might only care about files that were
> created after a certain time.
> {code:java}
> spark.readStream
> .option("header", "true")
> .option("delimiter", "\t")
> .format("csv")
> .load("/mnt/Deltas")
> {code}
> In
> [https://github.com/apache/spark/blob/f3771c6b47d0b3aef10b86586289a1f675c7cfe2/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/InMemoryFileIndex.scala],
> there is a method, _listLeafFiles,_ which builds _FileStatus_ objects
> containing an implicit _modificationDate_ property. We may already iterate
> the resulting files if a filter is applied to the path. In this case, its
> trivial to do a primitive comparison against modificationDate and a date
> specified from an option. Without the filter specified, we would be
> expending less effort than if the filter were applied by itself since we are
> comparing primitives.
> Having the ability to provide an option where specifying a timestamp when
> loading files from a path would minimize complexity for consumers who
> leverage the ability to load files or do structured streaming from a folder
> path but do not have an interest in reading what could be thousands of files
> that are not relevant.
> One example to could be "_filesModifiedAfterDate_" accepting a UTC datetime
> like below.
> {code:java}
> spark.readStream
> .option("header", "true")
> .option("delimiter", "\t")
> .option("filesModifiedAfterDate", "2020-05-01T12:00:00")
> .format("csv")
> .load("/mnt/Deltas")
> {code}
> If this option is specified, the expected behavior would be that files within
> the _"/mnt/Deltas/"_ path must have been created at or later than the
> specified time in order to be consumed for purposes of reading files from a
> folder path or via structured streaming.
> I have unit tests passing under _CSVSuite_ and _FileIndexSuite_ in the
> _spark.sql.execution.datasources_ package.
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